I'm a simple support who occasionally work with personal data stored in CSV and JSON. Libreoffice sucks. For example: deduplication hiden behind "create autofilters > press on any filter > filter by condition > standard filter > remove selected field > press options > no duplications". Cool, eh? And for some reason it doesn't work if at least one field selected, which is completely unintuitive. There other quirks too, like completely hidden in settings function to display more than 1 million rows, wich is disabled by default and there no notification that your document exceed this. I already forgot other issues that I faced with it, but yeah, not a fan of it. It's good untill you start actually use it.

That being said, it's free, open source and works most of the time, especially if you just need to view some data, from this side of things it have almost zero competition.